1. Field of the Invention
The present invention relates to an ultrasound endoscope that includes an ultrasound probe at a distal end side rigid portion of an insertion portion.
2. Description of the Related Art
Ultrasound endoscopes include a linear type and a convex type of ultrasound endoscope. An ultrasound probe that is mounted on a convex type ultrasound endoscope out of the above ultrasound endoscopes is placed onto an electric substrate (hereinafter called a transducer substrate) that is configured as, for example, a rigid substrate.
FIG. 12 is a sectional view showing an ultrasound probe that is placed at a distal end portion of a conventional ultrasound endoscope via a rigid substrate.
An ultrasound probe 121 has a convex type configuration integrally provided with an acoustic lens and the like, and is electrically connected to a transducer substrate 126 configured by a rigid substrate. The transducer substrate 126 is placed adjacently to a proximal end side of a nose piece 122 provided at the most distal end of an endoscope distal end portion.
Further, electric signals that are inputted to and outputted from the ultrasound probe 121 are transmitted via a cable 127. The cable 127 is configured by a plurality of signal lines 128 being covered with an overall shield 127a that has an electromagnetic wave shielding function, and a cable sheathing cover 127b having insulation properties. The cable 127 is such that in a proximal end side of a rigid portion 111 (an x-axis normal direction side), the cable sheathing cover 127b and the overall shield 127a are removed, and thereafter, the respective signal lines 128 are inserted to a transducer substrate 126 side via an insertion hole 101 provided in the rigid portion 111.
In the configuration as above, the respective signal lines 128 are connected to the transducer substrate 126 by soldering or the like, and therefore, the transducer substrate 126 needs a space 100A for soldering as illustrated. Accordingly, a height (a width in a y-axis direction) in FIG. 12 of the transducer substrate 126 is as illustrated in the drawing.
Further, in order to perform work of connecting the signal line 128 to the transducer substrate 126, a margin is required in the length of the signal line 128, and in order to extract the transducer substrate 126 which is still wired from the installation section for a repair or the like to be done at some future date, a margin is also required in the length of the signal line 128. Accordingly, the signal line 128 is configured to be somewhat long, and a space 100B for storage of an excessive length of the signal line 128 is required as illustrated in the drawing.
Furthermore, since the respective signal lines 128 have the cable sheathing cover 127b with insulating properties removed inside the insertion hole 101, an additional insulating member 100C configured by, for example, a polyimide pipe or the like is placed in the insertion hole 101, and the respective signal lines 128 are disposed in the insulating member 100C, in order to ensure insulating properties (voltage resistance) at a predetermined level of the signal lines 128 that is required in protection against electrical hazard.
Further, in place of the configuration in which the cable for transmitting electrical signals that are inputted to and outputted from the ultrasound probe is connected to the transducer substrate configured by a rigid substrate as described above, a configuration is also proposed, in which a flexible printed substrate is further provided, and a cable is connected to the flexible printed substrate.
For example, FIG. 1, FIG. 4 and the like of Japanese Patent Application Laid-Open Publication No. 2005-218519 indicate that in a convex type ultrasound endoscope, a rigid portion (9) and a bending portion (10) are provided to connect to an ultrasound transducer unit (20) at an insertion portion (2a) distal end, and that the ultrasound transducer unit (20) is configured to electrically connect an ultrasound transmission/reception portion (21) to a rigid substrate (35), and further electrically connect to a signal cable bundle (29) via a flexible printed substrate (33). In addition, Japanese Patent Application Laid-Open Publication No. 2005-218519 describes protecting connecting portions by folding the flexible printed substrate (33) to prevent the connecting portions of respective electrode portions (33b) of the flexible printed substrate (33) and respective signal core wires (29a) of the signal cable bundle (29) from being exposed to an outside.
Since a flexible printed substrate can change the shape thereof, the flexible printed substrate is folded in the above described Japanese Patent Application Laid-Open Publication No. 2005-218519, and as another shape change example, Japanese Patent Application Laid-Open Publication No. 2003-102732 is cited. FIG. 1 and the like of Japanese Patent Application Laid-Open Publication No. 2003-102732 describe an ultrasound probe (10) including an ultrasound transducer (20) for radial electronic scanning in which a number of ultrasound transducers (30) are arranged in a circumferential direction. The ultrasound probe (10) is used by being inserted through the inside of a treatment instrument insertion channel (6) of an endoscope (1), but since a diameter of the ultrasound transducer (20) is larger than a diameter of the treatment instrument insertion channel (6), a proximal end side of a flexible cord (22) provided with the ultrasound transducer (20) at a distal end side is inserted through the treatment instrument insertion channel (6). It is indicated that at this time, the flexible substrate (33) is connectively provided in an inclined direction at the proximal end side of the flexible cord (22) as shown in FIG. 2, FIG. 3 and the like, and in order to insert the flexible substrate (33) through the inside of the treatment instrument insertion channel (6) of the endoscope (1), the flexible substrate (33) is spirally wound into a cylindrical shape and is inserted into a sheath member (38). After the flexible substrate (33) is inserted through the treatment instrument insertion channel (6), the sheath member (38) is removed, and the flexible substrate (33) is developed to be connected to an ultrasound observation apparatus (11) via relay means (13).
Incidentally, there is proposed a rigid flexible substrate in which a rigid substrate and a flexible substrate are integrated, and as a configuration example thereof, Japanese Patent Application Laid-Open Publication No. 2010-16076 is cited. Japanese Patent Application Laid-Open Publication No. 2010-16076 describes a multilayer rigid flexible printed substrate including rigid portions (2A) and (2B) at both ends of a flexible printed substrate portion (1). As shown in FIG. 2 and FIG. 3, the multilayer rigid flexible printed substrate is of a stacked structure having a top coat layer (3) with electrical conductivity, a silver paste layer (4), copper foil (6) that has a pattern formed by etching and functions as a signal line and a GND pattern, a polyimide layer (7), and a cover lay (8). Out of the respective layers, the top coat layer (3) with electrical conductivity and the silver paste layer (4) are provided from the viewpoint of EMC (electro-magnetic compatibility), and function as shields.
FIG. 13 is a view showing a substrate connection structure of an ultrasound probe using a conventional rigid flexible substrate.
The ultrasound probe 121 is connected to the transducer substrate 126 that is configured by a rigid substrate in a rigid flexible substrate 124. From the transducer substrate 126, a flexible substrate portion 125 is extensively provided at a proximal end side, and a cable connection portion 125a is provided at a proximal end of the flexible substrate portion 125. The respective signal lines 128 of the cable 127 are connected to the cable connection portion 125a by soldering or the like.
If the configuration as above is used, the height of the transducer substrate 126 can be restrained, and reduction in diameter of the portion provided with the ultrasound probe in the endoscope distal end portion can be achieved as a result. Further, since connection of the respective signal lines 128 can be performed in the cable connection portion 125a at the proximal end side apart from the ultrasound probe 121, a working space at the time of wiring also can be ensured.